NEOTROPICAL SPECIES. 189 



Internal Anatomy. — Excepting the generative organs 

 there is nothing in the internal anatomy of this species which 

 deserves notice here. The generative organs, of which we have 

 an excellent description by Gaffron, do, however, present some 

 features of interest. The generative opening in both sexes is 

 between the legs of the penultimate pair. The oviduct end of 

 the ovary is directed forwards, and the ovarian ligament, which 

 is attached to the opposite end of the ovary, is of great length, 

 being attached to the pericardial floor between the twenty-fifth 

 and twenty- sixth pairs of legs. A globular receptaculum seminis 

 (with two short ducts) opens into the anterior part of each 

 oviduct. Immediately in front of the receptacula each oviduct 

 gives ofi' a short diverticulum, called " caecum " by Ernst, 

 "zipfelformige Anhang,''' and " ovarial-trichter ■" by Gaffron. 

 Gaffron, who at first thought that this process opened at its 

 free end into the body cavity, now accepts KenneFs statement 

 that it opens into a small vesicle with extremely thin walls. 

 Kennel calls this vesicle the receptaculum ovorum. I have 

 seen the process, but, unfortunately, have no observations on 

 its termination ; but I am strongly inclined, on theoretical 

 grounds, to think that Kennel is correct in his statement as to 

 the delicate vesicle. The generative ducts are the modified 

 nephridia of the segment on which the external opening is 

 placed : this is proved, on the one hand by their develop- 

 ment, and on the other by the fact that nephridia are absent 

 from the penultimate legs, between which the generative 

 opening is placed. Now, it has been shown by me (No. 39) 

 that all the nephridia open internally, not into the body cavity 

 as has been supposed, but into a small vesicle with extremely 

 delicate and thin walls. It thus appears that the presence of 

 this delicate vesicle of the receptaculum ovorum is another 

 proof — if another were wanted — that the oviducts of Peripatus 

 are modified nephridia. No such structure has been found in 

 the New Zealand species, but, possibly, further investigations 

 may come upon it. In Cap en sis, for reasons which I have 

 set forth elsewhere (No. 39), one would not expect to find this 

 structure. 



